public class Circle {
    double r,PI;
    Circle(){
        r = 4;
        PI = 3.14;
    }
    Circle(double r){
        this();
        this.r = r;
    }
    public void getArea(){
        System.out.println("圆的面积为：" + PI*r*r);
    }
    public void getCircle(){
        System.out.println("圆的周长为：" + PI*r*2);
    }
}
